1. Field of the Invention
This invention relates to the field of bats for use in ball games, and more particularly, to hollow metal bats having weighted end plugs and the process for manufacturing the bats.
2. Description of the Prior Art
A number of devices for affecting the weight distribution and/or vibration characteristics of bats and clubs are known in the art. In U.S. Pat. No. 4,241,919-Foreman, an aluminum baseball bat comprises a rubber plug at the extreme end of the striking portion of the bat. Gas pressure is varied with the hollow of the bat, behind the rubber plug, to control the vibration characteristics.
In U.S. Pat. 3,479,030-Merola, a rubber plug inserted in the end of a bat includes an enlargement which extends over the open end of the striking portion of the bat in a manner to form a smooth contour. The body of the Merola plug, however, is tapered such that the diameter is largest adjacent the end of the bat, and less towards the inside of the bat.
In U.S. Pat. No. 3,727,295-Gildmeister, an end plug is threadably attached to a metal bat having a foam-filled interior, and a flanged end extends over the metal. Although Gildmeister alternatively discloses a system of ridges for holding the rubber plug in the end of the bat, each of the foregoing references rely upon an adhesive connection between the plug and the hollow bat in order to maintain a plug in place. Foreman further discloses spinning the metal at the end of the bat to completely close the end over the solid plug. In the prior Foreman construction, there was no way to assure that the plug was actually positioned at the end of the bat. In fact, experience has proved that the spinning operation tended to force the plug away from the end of the bat.